Synthesis of Hydroxide Precursor Ni0.8Mn0.1Co0.1(OH)2 and Modeling the Effect of Ph on the Rate of Nucleation of Particles

Nickel-rich layered oxide cathode materials with the chemical formula of LiNi0.8Co0.1Mn0.1O2 (NCM) are increasingly utilized in the electric vehicle industry owing to their high energy density and high capacity. Although increasing the nickel concentration would enhance the chemical reaction between the surface layer and Li+/Ni2+ cationic mixing, the structural and thermal stability of the cathode material would be degraded. The single crystallization strategy of the particles can improve the structural stability and electrochemical performance of the cathode materials; however, their mechanism is not well understood yet. In this research, a computational model was proposed to show that by reducing the pH and controlling the amount of supersaturation, the nucleation rate of hydroxide particles and consequently the number of formed nuclei would decrease. Based on the results of this model, the numbers of hydroxide nuclei formed at the end of co-precipitation synthesis at pH 11.5, 11, and 10.5 were, respectively, 5.73, 4.3, and 2.27 times the number of nuclei formed in co-precipitation synthesis at pH 10. According to the observations, by reducing the pH during the synthesis process from 11.5 to 10, the fine particles produced in the system will be completely transformed into larger crystals, thus tending to become single crystals. As a result, the problems of the cathode/electrolyte intermediate layer will be minimized. The results of this model can justify the experimental results obtained by other researchers who synthesized single-crystal cathode materials.